The present disclosure relates to semiconductor structures, and particularly to semiconductor-on-insulator (SOI) field effect transistors with buried epitaxial active regions and methods of manufacturing the same.
Extremely thin semiconductor-on-insulator (ETSOI) semiconductor devices are fabricated on a very thin semiconductor layer, which typically has a thickness in a range from 2 nm to 30 nm. The thickness of the thin semiconductor layer is insufficient for formation of metal semiconductor alloy materials (such as metal silicide materials) employing conventional technology.
While formation of raised source and drain regions have been proposed as a potential solution, raised source and drain regions tend to have an undesirable effect of increasing Miller capacitance, which is the capacitance between a gate electrode and the source and drain regions. Another solution that employs polycrystalline source and drain regions has the undesirable effect of increasing on-resistance due to the grain boundaries that are inherently present in the polycrystalline semiconductor material.